Chaff bullet

ABSTRACT

A chaff bullet having a nose piece, a body and a rear section. The body encloses a chaff element which comprises a pair of half shells, each tapered at one end, and a plurality of chaff packettes positioned within the half shells. Each chaff packette includes several thousand elongated chaff which are enclosed by a thin wrapping of Mylar. When the chaff bullet is fired from a gun the tracer powder contained in the rear section burns slowly. After a predetermined time the increasing heat from the burning tracer powder causes ignition of an explosive in the body section which forces out the chaff element. The spin of the bullet causes outward release of the half shells and the chaff packettes. When the chaff packettes enter the air stream the Mylar wrapping is unwrapped which releases the chaff into the air in a well dispersed and undamaged condition.

United States Patent [191 Kulsik CHAFF BULLET [75] Inventor: Robert J.Kulsik, Livermore, Calif.

[73] Assignee: The United States of America as represented by theSecretary of the Navy, Washington, D.C.

[22] Filed: Jan. 28, 1972 [21] App1.No.: 221,498

[52] US. Cl 102/63, l02/37.6, 102/38,

[ 1 @ct. is, 1973 Primary Examiner-Robert F. Stahl AttorneyR. S.Sciascia [57] ABSTRACT A chaff bullet having a nose piece, a body and arear section. The body encloses a chaff element which comprises a pair,of half shells, each tapered at one end, and a plurality of chaffpaclcettes positioned within the half shells. Each chaff packetteincludes several thousand elongated chaff which are enclosed by a thinwrapping of Mylar. When the chaff bullet is fired from a gun the tracerpowder contained in the rear section burns slowly. After a predeterminedtime the increasing heat from the burning tracer powder causes ignitionof an explosive in the body section which forces out the chaff element.The spin of the bullet causes outward release of the half shells and thechaff packettes. When the chaff packettes enter the air stream the Mylarwrapping is unwrapped which releases the chaff into the air in a welldispersed and un- 7 damaged condition.

6 Claims, 14 Drawing Figures CHAFF BULLET BACKGROUND OF THE INVENTION 1.Field of the Invention The present invention relates to a chaff bullet,and more particularly, to a chaff bullet that effectively releases thechaff into the air in a well dispersed and undamaged condition.

2. Description of the Prior Art One of the difficulties encountered withprior chaff bullets was their inability to readily accomodate differentsizes and numbers of chaff. Another major difficulty was their inabilityto release the chaff into a large area where the released chaff was welldispersed and undamaged.

SUMMARY OF THE INVENTION The present invention overcomes the abovedescribed disadvantages of prior chaff bullets. Briefly, the presentinvention comprises a chaff bullet having a nose piece, a body and arear section. The body encloses a chaff element which comprises a pairof half shells, each tapered at one end, and a plurality of chaffpackettes positioned within the half shells. Each chaff packetteincludes several thousand elongated chaff which are enclosed in a thinwrapping of Mylar. When the chaff bullet is fired from a gun the tracerpower contained in the rear section burns slowly. After a predeterminedtime the increasing heat from the burning tracer powder causes ignitionof an explosive in the body section which forces out the chaff element.The spin of the bullet causes outward release of the half shells and thechaff packettes. When the chaff packettes enter the air stream the Mylarwrapping is unwrapped which releases the chaff into the air in a welldispersed and undamaged condition.

STATEMENT OF THE OBJECTS OF INVENTION An object of the present inventionis to provide an effective and reliable chaff bullet.

Another object of the present invention is to provide a relativelyinexpensive chaff bullet.

A further object of the present invention is to provide a bullet thatcan readily accomodate different sizes and numbers of chaff.

A still further object of the present invention is to provide a chaffbullet that releases the chaff into a large area where the releasedchaff is well dispersed and undamaged.

Other objects, advantages and novel features of the invention willbecome apparent from the following detailed description of the inventionwhen considered in conjunction with the accompanying drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic drawing of theassembled chaff round of the present invention;

FIG. 1A is a schematic drawing of the nose piece of the chaff bullet ofFIG. 1;

FIG. 1B is a schematic drawing of the body of the chaff bullet of FIG.1;

FIG. 1C is a schematic drawing of the rear section of the chaff bulletof FIG. 1;

FIG. 1D is the side elevation of the pair of half shells of the chaffbullet of FIG. 1;

FIG. IE is an end view of the pair of half shells of FIG. 1D;

FIGS. 2A and 2B are schematic drawings of the chaff element of FIG. 1;

FIGS. 2C and 2D are schematic drawings of the chaff packette of thechaff element of FIGS. 2A and 2B; and

FIGS. 3A through 3D are pictorial drawings showing the sequence ofoperation of the chaff bullet of FIG. 1.

In FIG. 1 is shown a 20 mm chaff round 11 which consists ofa shell 13and a chaff bullet 15. The subject of the present invention is the chaffbullet 15 and it is to be understood that the bullet may be made in avariety of sizes and shapes and is not to be limited in use with a 20 mmround. The chaff bullet 15 may be fired from the shell 13 from a gunmounted on a flying aircraft. Normally, there will be fired one chaffbullet for about five to ten live bullets fired from the gun.

Chaff bullet 15 includes a nose piece 17, a body 19, and a rear section21. Nose piece 17 is illustrated in FIGS. 1 and 1A and has an exteriorconfiguration, as shown, and includes an elongated cylindrical interiorsection 23 that includes threads 25 shown by the dotted lines in FIG.1A. The threads 25 are provided for tooling which is used in themanufacturing process of the nose piece. The rear section of nose piece17 has an enlarged cavity 27 having a cylindrical section 29 and aconical section 31. The cylindrical section 29 has a diameter a which isslightly smaller than the diameter b of body 19, as shown in FIG. 18. Itshould be noted that the rear surface 33 of nose piece 17 abuts againstthe forward surface 35 of body 19 when assembled, as illustrated inFIG. 1. As will be hereinafter explained in greater detail, whenassembled the tapered ends 37 and 37' of half shells 39 and 39 are inforced engagement with cylindrical surface 29.

Referring to FIGS. 1 and 18, body 19 includes a circular groove 41 forreceiving ring 43 and circular groove 45 for receiving circular detent47 of shell 13. The rear section of body 19 is provided with femalethreads 49 for receiving male threads 50 of rear section 21 of FIG. 1C.

Rear section 21 of FIG. 1C includes a tracer element 51 that comprises acup having a steel cylindrical wall 53 and a steel bottom section 55.The cup is filled with tracer powder 57 and is closed by means ofclosure 59 which is made ofa foil material such as a heavy gaugealuminum foil. Rear section 21 also includes an explosive charge 61which may be bulls-eye pistol powder. for example. Closure 62, which maybe made of aluminum foil, seals the explosive charge 61 in place andholds it against the forward surface of bottom section 55. Tracerelement 51 is retained in position by means of circular lip 63 whichprevents the tracer element from being blown out by ignition ofexplosive charge 61.

Shell 13, which may be a 20 mm shell, for example, includes cap 65,elongated section 67 and explosive powder 69. Upon being fired by thegun, the powder within cap 65 ignites explosive charge 69 which in turnignites the powder in tracer element 57, rapidly transmitting its heatthrough foil 59, and propels chaff bullet 15 in the forward direction.

In FIGS. 2A and 2B is illustrated the chaff element 71 used in the chaffbullet 15 of FIG. 1. Chaff element 71 includes half shells 39 and 39,shown in FIGS. 1D, 1E, 2A, and 2B, which contain four chaff packettes73, as illustrated by the dotted lines of FIGS. 2A and 2B. It is to beunderstood that more or less than four packettes may be employed and oneor more of them may be dummy packettes. Also, depending upon theparticular needs, the packettes may be selected to have differentlengths. In FIGS. 2C and 2D is illustrated a single chaff packette 73.The chaff 75, comprising approximately 20,000 pieces of very small metalcovered glass rods, are packed into half shells 77 and 77 of chaffpackette 73. One method for achieving this described chaff packettestructure is to draw 20,000 lengths of chaff 75 through a one-fourthinch soda straw, then cut the straw to length and then make two slitslengthwise in the straw to form half shells 77 and 77. The chaff filledhalf shells 77 and 77' are then wrapped by a thin Mylar wrapping 79having a width that is the same as the length of the half shells. It hasbeen found that a four-inch length of Mylar film is very effective inthat it provides an adequate time interval before release at the chaffafter the packette is introduced into the air stream as will behereinafter described in detail.

Referring now to FIG. 1, the assembled chaff bullet includes chaffelement 71 that is inserted into body 19. The tapered ends 37, 37' ofhalf shells 39, 39' extend beyond the end of body 19. The outsidediameter of chaff element 71 is very slightly larger than the insidediameter b of body 19 and is forced into body 19 and is held in place bya snug fit. Also, the outside diameter of chaff element 71 issubstantially larger than the inside diameter a of nose piece 17. Nosepiece 17 is held in position by forcing it over tapered ends 37, 37until rear surface 33 of nose piece 17 abuts against forward surface 35of body 19. A metal piston 81, which is preferably made of aluminum,abuts against the flat end of chaff element 71 and a washer 83,preferably made of Teflon, abuts against piston 81. Washer 83 functionsto absorb the shock when the bullet is initially fired from the gun.Rear section 21 is mounted on the end of body 19 by means of threads 49and 51 and shell 13 is mounted on the rear part of body 19.

The following is a description of the operation of chaff round 11 whenfired from a gun. The operation is initiated when the gun hammer strikescap 65 of shell 13. When this occurs the powder in cap 65 ignites whichin turn ignites explosive charge 69. The ignition of explosive charge 69simultaneously projects the chaff bullet 15 down the gun barrel andignites powder 57. While the chaff bullet 15 travels down the barrel,the rifling of the gun spins the bullet. This rotational spin of thechaff bullet is important for its effective operation. As the powder 57in tracer element 51 burns, it causes a progressive temperature increaseof steel bottom section 55. When the temperature of bottom section 55reaches about l,000 F, which occurs when the chaff bullet 15 is about4500 feet from the gun, then explosive charge 61 is ignited by thiselevated temperature. It should also be noted that bottom section 55 oftracer element 51 is sufficiently strong to not blow out when explosivecharge 61 ignites. When explosive charge 61 ignites, the pressuregenerated thereby acts against piston 81 which, being abutted againstthe flat surface of chaff element 71, forces chaff element 71 out frombody 19. This sequence of operation is pictorially illustrated in FIG.3B. As soon as the chaff element 71 leaves the end of body 19 then theflat end of the half shells 77 and 77 are free to move outward and willfly open due to the centrifugal force caused by its rotation. This ispossible because the taper of tapered ends 37 and 37' permits the shellsto pivot about point C (see FIG. 1D) such that the flat ends will rotateoutwards due to the centrifugal force. When the half shells 39, 39' flyoutward then the chaff packettes 73 are released and fly outward bycentrifugal force. This sequence of operation is pictorially illustratedin FIG. 3C. When the packettes 73 enter the wind stream then the windunwinds the wrapping 79 from the chaff 75. This releases the chaff 75 inan undamaged condition into a large area of uniform dispersement andthereby provides an effective radar decoy. This sequence of operation ispictorially illustrated in FIG. 3D. It should be particularly noted thatthe wrapping 79 protects the chaff 75 and allows sufficient time for thechaff to slow down and travel outward before releasing half shells 77,77 and the chaff 75 contained therein. Normally, the chaff bullet istraveling at about 1,000 feet per second when the chaff element isexpelled from the bullet body.

What is claimed is:

1. A chaff bullet comprising:

a. a nose piece, a body and a rear section;

b. said rear section being operatively connected to the rear end of saidbody;

c. a chaff element;

(1. said chaff element being mounted within said body;

e. said chaff element comprising a pair of half shells and at least onechaff packette mounted within said half shells;

f. each of said half shells includes a tapered end;

g. said nose piece including a cavity; and

h. each of the tapered ends of said half shells extends beyond the frontend of said body and into said cavity of said nose piece to retain saidnose piece in position.

2. The chaff bullet of claim 1 wherein:

a. said at least one chaff packette includes a plurality of elongatedchaff that is wrapped by a strip of thin plastic wrapping.

3. The chaff bullet of claim 4 wherein:

a. a pair of half shells are positioned between said chaff and saidwrapping.

4. The chaff bullet of claim 1 wherein:

a. each of said half shells includes a flat end;

b. the flat ends of said half shells are positioned near the rear end ofsaid body; and

c. a piston is positioned adjacent said flat ends of said half shellsfor driving said chaff element from said body.

5. The chaff bullet of claim 4 including:

a. a washer made of energy absorbing material positioned between saidpiston and said rear section.

6. The chaff bullet of claim 6 wherein:

a. said rear sections include a tracer element containing a tracerpowder and an explosive charge; and

b. a metal section positioned between said tracer powder and saidexplosive charge.

1. A chaff bullet comprising: a. a nose piece, a body and a rearsection; b. said rear section being operatively connected to the rearend of said body; c. a chaff element; d. said chaff element beingmounted within said body; e. said chaff element comprising a pair ofhalf shells and at least one chaff packette mounted within said halfshells; f. each of said half shells includes a tapered end; g. said nosepiece including a cavity; and h. each of the tapered ends of said halfshells extends beyond the front end of said body and into said cavity ofsaid nose piece to retain said nose piece in position.
 2. The chaffbullet of claim 1 wherein: a. said at least one chaff packette includesa plurality of elongated chaff that is wrapped by a strip of thinplastic wrapping.
 3. The chaff bullet of claim 4 wherein: a. a pair ofhalf shells are positioned between said chaff and said wrapping.
 4. Thechaff bullet of claim 1 wherein: a. each of said half shells includes aflat end; b. the flat ends of said half shells are positioned near therear end of said body; and c. a piston is positioned adjacent said flatends of said half shells for driving said chaff element from said body.5. The chaff bullet of claim 4 including: a. a washer made of energyabsorbing material positioned between said piston and said rear section.6. The chaff bullet of claim 6 wherein: a. said rear sections include atracer element containing a tracer powder and an explosive charge; andb. a metal section positioned between said tracer powder and saidexplosive charge.